The subject matter disclosed herein relates generally to overload relays, and, more particularly, to a modular electronic overload device adapted to allow for easier commissioning and replacement.
Overload relays are current sensitive relays that can be used to disconnect power from equipment when an overload or other sensed condition exists. They are normally used in conjunction with an electromechanical contactor, and are designed to protect an electric motor or other electronic devices.
In a typical installation, the contactor provides three contacts, one associated with each of up to three phases of power, that are closed by an electromagnetically operated contactor coil. The overload relay includes current sensing elements that are wired in series with the three phases passing through the contactor to the motor. In this way, the overload relay can monitor current flowing in the three phases through the contactor, and based on current magnitude and duration, may interrupt the current flow through the contactor coil circuit to open the contactor contacts when an overload occurs. For this purpose, the overload relay includes a contact or contacts that can be used to control the contactor coil and/or provide a signal indicating an overload or other sensed condition.
One difficulty associated with overload relays in general is the complexity in commissioning a motor control panel where multiple motor control circuits are required. Today there are two common installation methods. One installation method is to have each motor starter in an individual compartment. The second method is to mount multiple motor starters side by side in one enclosure. After the motor starters are mounted and wired, a system integrator has the responsibility to configure each intelligent electronic overload device. As motor control devices have become more sophisticated, the level of complexity involved in configuring each intelligent electronic overload device to match up to an associated motor system has become quite challenging. A system integrator may be required to configure a local human-machine interface device (hereinafter “HMI”), and/or a network device to properly configure an intelligent electronic overload device. To perform the required configuration, the system integrator may require a personal computer. Due to the complexity associated with configuring multiple parameters, configuration of a single intelligent electronic overload device task could take hours. Furthermore, after the intelligent electronic overload device itself is properly configured, the system integrator may then need to establish communications between the intelligent electronic overload device and a networked system such as an automation control system, resulting in more time expended to fully configure the intelligent electronic overload device. Finally, due to the different types of communication networks available in the market, each deployment may require additional configuration or special wiring, further increasing the amount of time required to commission a motor control system and/or the potential for human error.
Additionally, another difficulty associated with intelligent electronic overload devices is the time required to configure a replacement intelligent electronic overload device. Currently, maintenance personnel often require access to a personal computer in order to configure a replacement intelligent electronic overload device, to which they may not have immediate access to when needed. Lack of access to a properly configured personal computer, combined with the above mentioned difficulty associated with configuring complex intelligent electronic overload devices, can result in unnecessary downtime as well as lost production time when an intelligent electronic overload device must be replaced.
Another difficulty associated with intelligent electronic overload devices in general is the large number of catalog numbers that need to be manufactured and warehoused. Typically, an overload device is designed for only a limited current range, and, possibly, a limited, fixed set of functional options. If you are a manufacturer, you want to offer a full product line, which means offering a large variety of overload relays that operate at their respective currents. Thus, an integrator or an original equipment manufacturer (“OEM”) using overload relays needs to have a large selection of overload relays available to meet the needs of the designed application. Attempts to accommodate overload relays to operate in a wider range of applications can result in increased size, cost, and heat generation. Similarly, intelligent electronic overload devices with many available options have multiple product configuration files to identify the specific options that were selected for that system. This could result in thousands of different configuration files which can be very difficult to manage. A large number of different configuration files can also create significant complexity for the creation of collateral application software as well.
For example, intelligent devices may require configuration files such as Electronic Data Sheet (hereinafter “EDS”) files in order to be used in an intelligent system. These EDS files are generally created to correspond with each catalog number. Where there may be a large number of catalog numbers, such as when a separate catalog number is needed to address multiple options and parameters, this would result in a equally large number of EDS files. These files must first be created, consuming valuable resources. Furthermore, these files are often obtained by the end user via an electronic download. Where a large number of EDS files exists, an end user may have to spend a significant amount of time searching for the EDS file that correspond to a particular intelligent device. Additionally, where a large number of catalog numbers exist, multiple software application profiles, such as “Add On Instructions” used in an environment such as RSLOGIX, or “Faceplates” required when interfacing to a visualization device 118 such as a PANELVIEW product from Rockwell Automation, may also be required.
Finally, current intelligent devices such as intelligent electronic overload devices can often be used as remote control modules. This allows a user to utilize the power of the devices to configure the I/O on the device for specific applications. This is often done using an industrial automation programming architecture such as RSLOGIX from Rockwell Automation. However, this often required a sophisticated user with a programming device, such as a personal computer with the necessary programming software, to program the intelligent device. However, often the devices were configured to correspond with commonly used application configurations. In these instances, the ability for a user to quickly configure an intelligent device such as an intelligent electronic overload device for a common application could significantly reduce installation and commissioning time for industrial automation systems.
There is a need, therefore, for a modular overload relay assembly that can be easily configured with or without a personal computer when installing or replacing an intelligent electronic overload device. Furthermore, there is a need for an intelligent electronic overload device to have a single configuration file, such as an EDS file, with a common set of user-selectable parameters contained within the intelligent electronic overload device. Finally, there is a need to have an intelligent electronic overload device that can have embedded software function blocks that a user can select to place the device into a desired operational mode without a user being required to program the device, as has been done traditionally.